1. Field of the Invention
The present invention relates generally to wheeled carts or dollies for transporting carrying cases or luggage and, more particularly, to collapsible wheeled carts for transporting carrying cases and to convertible carrying case systems having a carrying case and a removably attachable wheeled cart by which the carrying case is converted into a rolling carrying case when attached to the wheeled cart and is converted into a non-rolling carrying case when disassociated from the wheeled cart.
2. Discussion of the Related Art
Carrying cases or luggage are conventionally available in a variety of external sizes providing different sizes of interior storage space for holding contents within the carrying cases. Conventional carrying cases are commonly available in sizes ranging from very large carrying cases such as suitcases to smaller size carrying cases such as carry-on bags and briefcases. Carrying cases specifically designed to hold notebook or laptop computers are available. Some conventional carrying cases are rolling carrying cases provided with attached wheels which allow the carrying cases to be rolled along the ground, floor or other transport surface. Other conventional carrying cases are provided without attached wheels and are non-rolling carrying cases. Non-rolling carrying cases must normally be manually lifted and carried by the user in order to be transported from place to place, the lifting and/or carrying ordinarily being accomplished via a handle and/or a shoulder strap on the carrying case. The handles of non-rolling carrying cases are typically fixed handles attached to an external wall of the carrying case. In a grasping position for the handles, a hand grip of the handle is normally closely spaced from the external wall to accommodate the user's fingers between the hand grip and the external wall. Fixed handles are different from extendible and retractable handles in that the hand grips are not movable or are not movable an appreciable amount from the grasping position away from and toward the external wall. When non-rolling carrying cases are transported by lifting and carrying, the user must normally support the entire weight of the carrying case.
The need to transport non-rolling carrying cases by manual lifting and carrying can be very physically demanding where the carrying cases are relatively bulky and/or heavy and/or must be carried relatively long distances. Even where non-rolling carrying cases are not especially bulky and/or heavy and/or carried relatively long distances, the act of manually transporting such carrying cases can still be physically demanding for individuals having physical limitations. Aside from being physically demanding, manually transporting non-rolling carrying cases by lifting and carrying is oftentimes simply inconvenient for users, and the inconvenience may be compounded where the user has one or more other items to carry at the same time as the carrying case.
Rolling carrying cases are generally easier to transport from place to place than non-rolling carrying cases. Rolling carrying cases are normally provided with an extendable and retractable handle selectively movable between a retracted handle position where the hand grip of the handle is close to an external wall of the carrying case and an extended handle position where the hand grip is spaced an appreciably greater distance from the external wall of the carrying case as represented by U.S. Pat. No. 6,802,409 B1 to Tiramani et al. The extendable and retractable handles may thusly be considered adjustable in height. The distance that the hand grip is spaced from the external wall in the extended handle position is sufficient to allow the carrying case to be pulled or pushed by the user, while standing or erect, via the hand grip to roll the carrying case on its wheels along the ground, floor or other transport surface without the need for manually lifting and carrying the carrying case. In many instances, the wheels are provided along one side of the carrying case so that pushing or pulling the carrying case via its hand grip involves tipping the carrying case onto its wheels from an upright vertical orientation to elevate the opposite side of the carrying case above the transport surface. In addition to being used to effect rolling movement of the carrying case along a transport surface, the handle in the extended handle position may serve as a structural support for the carrying case and/or another object stacked on top of the carrying case and transported therewith. When the rolling function is not needed, the handle is usually moved to the retracted handle position. In most rolling carrying cases, a separate fixed handle is provided for manually lifting and carrying the carrying case when the extendable and retractable handle is in the retracted handle position. The extendable and retractable handles found on rolling carrying cases are necessarily of greater structural complexity than the fixed handles of non-rolling carrying cases.
It is to be expected that rolling carrying cases will still be manually lifted and carried some of the time in the same manner as non-rolling carrying cases. However when rolling carrying cases are to be used exclusively or primarily as non-rolling carrying cases, i.e. without utilizing the rolling function for a considerable length of time, the wheel structure, the more complex handle structure and/or any other structure associated with the rolling function constitute extraneous components which undesirably add to the weight and/or bulk of the carrying case. In addition, when rolling carrying cases are supported in an upright vertical orientation on a support surface, the attached wheels thereof may make sliding contact with the support surface. In some carrying cases the sliding contact between the wheels and the support surface makes it difficult for the carrying case to remain in the upright vertical orientation on the support surface without tipping or falling over. The wheels also present external protuberances which may get caught on and/or damage other objects. While it would be desirable to remove the wheels of rolling carrying cases when the rolling function is not needed for a considerable length of time, the wheels are typically either permanently attached to or are not quickly and easily removable from the carrying cases. Accordingly, conventional rolling carrying cases cannot be selectively converted into non-rolling carrying cases and converted back into rolling carrying cases quickly and easily on demand in accordance with user preferences and needs.
Wheeled luggage carts or dollies for transporting non-rolling carrying cases have been proposed. Generally, such luggage carts comprise a luggage support platform associated with a plurality of wheels and with a frame presenting a handle by which the cart, with a carrying case supported on the luggage support platform, can be pushed or pulled along a transport surface via the wheels. Usually the luggage support platform is designed to support the carrying case thereon in a luggage support plane so that the carrying case remains level and balanced while being rolled along the transport surface. The wheels may be mounted at or near the rear of the luggage support platform, with the wheels being spaced from one another for rotation on the transport surface in spaced apart planes perpendicular to the transport surface. The frame may extend upwardly from the luggage support platform at an angle of about 90° to the luggage support plane. By placing a non-rolling carrying case on the luggage support platform of a wheeled cart, the non-rolling carrying case can be temporarily used in a manner similar to a rolling carrying case. Unfortunately, conventional wheeled luggage carts are in general not designed to facilitate intermittent use of the carrying case as a non-rolling carrying case while the carrying case remains associated with the cart. Instead, the carrying case must normally be completely disassociated from the wheeled cart, at considerable inconvenience to the user, in order to be used as a non-rolling carrying case even for a brief time.
In order to be available for use on demand, wheeled luggage carts are oftentimes treated as an accessory to carrying cases, with users taking wheeled luggage carts on trips along with their carrying cases or luggage. To facilitate portability and/or storage of wheeled luggage carts when not being used to transport a carrying case, many wheeled luggage carts are designed to be collapsible or foldable from an open or expanded operative configuration when being used to transport a carrying case to a closed or collapsed inoperative configuration when not being used to transport a carrying case. The carts have a more compact size and configuration in the collapsed configuration than in the expanded configuration, and it is desirable for the size and configuration to be minimized as far as possible in the collapsed configuration so that the carts are easier to transport and/or store when not in active use. Nevertheless, many conventional luggage carts have a size and configuration in the collapsed configuration that is too large for the collapsed carts to be stowed in relatively small spaces such as the space beneath an airplane passenger seat and/or the space within the interior of the carrying cases themselves. Collapsible wheeled carts for transporting carrying cases or luggage are represented by U.S. Pat. No. 6,447,002 B1 to Fang, U.S. Pat. No. 6,012,729 to Lin, U.S. Pat. Nos. 5,984,327 and 5,951,037 to Hsieh et al, U.S. Pat. No. 5,803,471 to DeMars et al, U.S. Pat. No. 5,439,239 to Su, U.S. Pat. No. 5,401,043 to Myron, U.S. Pat. No. 5,348,325 to Abrams, U.S. Pat. No. 5,263,727 to Libit et al, U.S. Pat. No. 4,969,660 to Spak, U.S. Pat. No. 4,743,038 to Myers et al and U.S. Pat. No. 4,684,141 to Nunokawa et al.
Collapsible wheeled luggage carts commonly have extendible and retractable handles selectively movable between extended and retracted handle positions. The height of the handles in relation to the luggage support platform is greater in the extended handle position than in the retracted handle position so that the height of the handles is adjustable through handle extension and retraction. Extension and retraction of the handles is sometimes accomplished by virtue of hinged or pivotally connected handle sections as illustrated by the Su, Abrams and Spak patents. In other wheeled carts, extension and retraction of the handles is accomplished via slidable telescoping handle sections as illustrated by the Fang, Lin, Hsieh et al, DeMars et al, Myron, Libit et al, Myers et al and Nunokawa et al patents. Where the handles are telescoping, various mechanisms have been proposed to lock the handles in a selected handle position and to release the handles for telescoping movement to another handle position. In the Hsieh et al ('327) and DeMars et al patents, push buttons are provided for releasing the handles for telescoping movement. The handles of collapsible carts are in the extended handle position when the carts are in the expanded operative configuration and are in the retracted handle position when the carts are in the collapsed inoperative configuration. The height of the handles ordinarily extends in the same or substantially the same direction as the overall height of the luggage carts and defines at least a portion of the overall height of the luggage cart. Accordingly, the carts ordinarily are of increased overall height in the expanded operative configuration due to handle extension and are of decreased overall height in the collapsed inoperative configuration by virtue of handle retraction. The extendible and retractable handles of collapsible luggage carts thusly allow the overall height of the luggage carts to be adjusted, with the overall height being reduced in the collapsed configuration from the overall height in the expanded configuration.
In addition to being of decreased overall height in the collapsed inoperative configuration and being of increased overall height in the expanded operative configuration, most collapsible luggage carts have their overall depth decreased when placed in the collapsed inoperative configuration from the expanded operative configuration and have their overall depth increased when placed in the expanded operative configuration from the collapsed inoperative configuration. A decrease in overall depth is commonly obtained in the collapsed configuration by placing the luggage support platforms in a non-deployed position from a deployed position and, by placing the luggage support platforms in the deployed position from the non-deployed position, increased overall depth is obtained in the expanded configuration. In the deployed position, the luggage support platforms are typically disposed at an angle of about 90° to the frames. The luggage support platforms in the deployed position extend in the same or substantially the same direction as the overall depth of the luggage carts and thusly define at least a portion of the overall depth perpendicular to the overall height. In the non-deployed position, the luggage support platforms are typically placed close to the frames and extend in the same or substantially the same direction as the frames such that the carts have an overall depth in the collapsed configuration appreciably smaller than the overall depth of the carts in the expanded configuration for a slimmer, flatter profile. In many collapsible luggage carts, the luggage support platforms have a non-deployed position where the luggage support platforms lie parallel or substantially parallel to the frames.
To facilitate movement of the luggage support platforms between the deployed and non-deployed positions, collapsible luggage carts have been proposed wherein the luggage support platforms are pivotally mounted to the frames. The Fang patent is representative of a collapsible luggage cart in which the frame is pivoted relative to the luggage support platform from a position perpendicular to the luggage support platform in the deployed position to a position close to and parallel with the luggage support platform in the non-deployed position. The Lin, Hsieh et al ('327 and '037), DeMars et al, Su, Myron, Abrams, Libit et al, Spak and Myers et al patents are representative of collapsible luggage carts in which the luggage support platforms are pivoted relative to the frames from a position at an angle of about 90° to the frames in the deployed position to a position where the luggage support platforms lie parallel or substantially parallel and/or close to the frames in the non-deployed position. The Nunokawa et al patent is representative of a collapsible luggage cart where the frame must be detached from and placed alongside the luggage support platform to obtain the non-deployed position and must be reattached to the luggage support platform at a 90° angle to obtain the deployed position.
In some collapsible luggage carts, the wheels are in a deployed position when the carts are in the expanded operative configuration and are moved to a non-deployed position when the carts are placed in the collapsed inoperative configuration for greater overall depth reduction. For example, the wheels in the deployed position may protrude a considerable distance rearwardly beyond the frame and/or the luggage support platform in the direction of the overall depth, in which case the wheels define at least a portion of the overall depth. In order to minimize the impact of wheel protrusion on the size of the overall depth and obtain a flatter profile in the collapsed configuration, luggage carts of this type have been proposed in which the wheels themselves are rotated from a deployed position for the wheels in which the wheels are parallel or substantially parallel to one another in the expanded operative configuration for the luggage cart to a non-deployed position for the wheels where the wheels lie coplanar or substantially coplanar close to or in line with the frame in the collapsed configuration for the luggage cart to obtain a flatter depth profile. Collapsible luggage carts in which the wheels are moved to assume a coplanar or substantially coplanar arrangement close to the frame in a non-deployed position for the wheels are represented by the Fang, Hsieh et al ('327), DeMars et al, Su, Abrams, Libit et al and Spak patents. Notably, in the luggage carts disclosed in the Hsieh et al ('327), DeMars et al, Su, Abrams, Libit et al and Spak patents, the overall width of the carts in the collapsed inoperative configuration remains the same or substantially the same as the overall width in the expanded operative configuration despite the wheels being moved to their non-deployed position in the collapsed configurations. Accordingly, many collapsible luggage carts are designed only for an appreciable reduction in overall height and overall depth when placed in the collapsed inoperative configuration from the expanded operative configuration, with the overall width of the carts being the same or substantially the same in both the expanded and collapsed configurations. Since the overall width dimension in the expanded operative configuration is oftentimes substantial in size due to various factors including the spacing between the wheels in their deployed position, the inability to decrease the overall width when the carts are placed in the collapsed configuration limits the compactness and portability achieved for the luggage carts in the collapsed configuration.
Collapsible luggage carts which are capable of having each of their overall width, overall height and overall depth appreciably reduced in size when placed in the collapsed inoperative configuration from the expanded operative configuration are represented by the Fang, Myron, Meyers et al and Nunokawa et al patents. The Fang and Nunokawa et al patents are representative of luggage carts in which overall width reduction is accomplished by pivoting or folding side sections of the luggage support platform inwardly toward one another relative to a central section of the luggage support platform. The wheels of the carts are mounted to the side sections and move therewith. As a result of the side sections pivoting or folding inwardly toward one another, the carts have an overall width in the collapsed configuration less than that in the expanded configuration. The greater overall width of the carts in the expanded configuration is obtained by pivoting or unfolding the side sections outwardly away from one another relative to the central section so that the side sections are coplanar or substantially coplanar with the central section. The Myron patent is illustrative of a collapsible cart in which overall width reduction in the collapsed configuration is obtained by decreasing the frame width. The frame comprises legs spring biased outwardly away from one another to assume an inverted V-shaped configuration in the expanded configuration. Lower ends of the legs carry the wheels, and the legs are squeezed together to assume an essentially parallel configuration close to one another in the collapsed configuration for reduced width. In the collapsible cart disclosed by Myers et al, the frame width is reduced in a different manner than the Myron patent to obtain overall width reduction in the collapsed configuration. The frame comprises L-shaped legs disposed in a common plane and having leg segments extending outwardly in opposite directions in the direction of the overall width of the cart in the expanded configuration. The leg segments have outer ends carrying the wheels, and the leg segments are rotated about 180° inwardly toward one another for reduced overall width in the collapsed configuration.
Collapsible luggage carts that provide size reduction in three dimensions, i.e. height, depth and width, when placed in their collapsed configurations from their expanded configurations are advantageous for the greater compactness and portability afforded thereby. However, a drawback of these luggage carts and collapsible luggage carts in general relates to the operational complexity associated with placing the carts in their expanded configurations from their collapsed configurations as well as with placing the carts in their collapsed configurations from their expanded configurations.
In many collapsible luggage carts, the luggage support platforms must be placed manually in their deployed position by moving the platforms directly to obtain the proper orientation for the platforms relative to the frames in the expanded configuration. Direct manual engagement of the luggage support platforms in order to place the luggage support platforms in their deployed position requires physical exertion and the awkward use of two hands by the user such that the luggage carts cannot be opened or expanded quickly and easily on demand. Although luggage carts have been proposed in which a single manual operative motion effects two operational functions simultaneously, the operational functions accomplished with the single manual operative motion obtain only the increased depth for the carts in the expanded configuration. For example, in the luggage carts represented by the Hsieh et al ('327), DeMars et al, Abrams and Spak patents, direct manual pivotal movement of the luggage support platform from its non-deployed position to its deployed position also causes the wheels to be moved from their non-deployed position to their deployed position but achieves only the increased depth in the expanded configuration. Collapsible luggage carts in which both the depth and width must be increased to place the carts in the expanded operative configuration from the collapsed inoperative configuration, as represented by the Fang, Myron, Myers et al and Nunokawa et al patents, require a plurality of separate, different, independent and distinct manual operative motions to obtain the increased depth and width when the carts are placed in the expanded configuration from the collapsed configuration. The operational complexity associated with placing the carts in the expanded configuration is compounded where a plurality of separate, different, independent and distinct manual operative motions are required. Furthermore, the physical exertion, inconvenience and increased time required to place the carts in their expanded configuration from their collapsed configuration are also compounded when a plurality of separate, different, independent and distinct manual operative motions are required. Accordingly, there is an unfulfilled need for collapsible wheeled luggage carts in which the operational functions needed to deploy the luggage support platforms and the wheels to obtain increased depth and width when placing the carts in the expanded configuration from the collapsed configuration can be effected quickly and easily with minimal effort and inconvenience using a single, simple manual operative motion. There is also an unfulfilled need for collapsible wheeled luggage carts capable of being placed in their collapsed configuration from their expanded configuration by reversing the single, simple manual operative motion used to place the carts in the expanded configuration from the collapsed configuration.
Another disadvantage of conventional luggage carts relates to the manner in which a carrying case is maintained on the luggage cart. Where a carrying case is merely supported on the luggage support platform without being structurally or mechanically secured to the luggage cart in any way, the carrying case is at risk of falling off the luggage cart accidentally. This risk can be reduced where the width and depth of the luggage support platform are greater than or close in size to the width and depth of the carrying case for better support and stability, but a smaller size platform width and depth would be preferable in order to minimize the weight, bulk, size and cost of the luggage cart. A luggage cart in which the luggage support platform has a width and depth appropriate to support a particular size carrying case may be larger than necessary to support smaller size carrying cases and/or smaller than necessary to support larger size carrying cases, thereby limiting the types and sizes of carrying cases that can be used interchangeably with the luggage cart. Many luggage carts are used with straps or cords to secure a carrying case in position on the luggage cart. The need for users to apply straps or cords is inconvenient, tedious and time consuming, and the attachment provided by straps or cords may prove to be unreliable. It has also been proposed to removably attach a carrying case to a luggage cart by releasably engaging a connector element on the carrying case with a corresponding connector element on the luggage cart as represented by U.S. Pat. No. 5,749,446 to Hsieh and U.S. Pat. No. 5,024,455 to Schrecongost and by the Lin, Hsieh et al ('037) and Myers patents. The connector elements can be difficult to properly align for interengagement, and engagement and/or release of the connector elements is also made more difficult by their structural and/or operational complexity. The need exists, therefore, for improvements relating to the releasable attachment of carrying cases to luggage carts which are more simple and user friendly while establishing a reliable structural attachment between the carrying cases and the luggage carts.
Where conventional luggage carts are designed for structural or mechanical attachment to a carrying case, the luggage carts and attached carrying cases tend to be lacking in structural continuity and integration in that the luggage carts still appear structurally separate from and not structurally integrated with the attached carrying cases in an aesthetically appealing manner. It would be preferable from an aesthetic standpoint for the luggage carts and attached carrying cases to convey the visual appearance of structural unity and integration similar to rolling carrying cases with built-in extendable and retractable handles and built-in wheels. Luggage carts which attach to carrying cases oftentimes have physical dimensions which do not correspond proportionally to the attached carrying cases, thereby exacerbating the lack of structural continuity and integration. In addition, carrying cases that structurally attach to luggage carts are generally not suitable for being manually lifted and carried while remaining attached to the associated luggage cart and are therefore not suitable for use in a manner similar to non-rolling carrying cases unless the carrying case is completely disassociated from the cart. For greater versatility and ease of use, it would be preferable to facilitate manual transport of a carrying case by lifting and carrying while the carrying case is structurally attached to a luggage cart. In this manner, the carrying case can remain attached to the luggage cart when the rolling function is not being used without the luggage cart interfering with use of the carrying case in the manner of a non-rolling carrying case, and it would be beneficial for the carrying case to be convertible into a rolling carrying case simply by extending the handle of the attached luggage cart.